In general, in robotics, a manipulator is a device used to manipulate materials without direct human contact. Manipulator applications were originally for dealing with radioactive or biohazardous materials or they were used in inaccessible places. In more recent developments they have been used in applications such as robotically-assisted surgery and in space. A manipulator may be an arm-like mechanism that consists of a series of segments, usually slide, pivoted or jointed, which grasp and move objects with a number of degrees of freedom.
Currently, systems comprise tactile sensors which require contact with the manipulator before sensing the object. These tactile sensors have some sort of contact sensing typically covered by compliant ‘skin’. This form of sensing is currently being explored and developed. These tactile sensors require very cautious slow movement when the location of the object contains some uncertainty. Likewise, there are optical distance sensors that are used for obstacle avoidance in robot navigation, but not specifically for the use of grasping and manipulation. Currently, grasping and manipulation is one of the most difficult robotic challenges. Improving the ability for grasping is important for the advancement of robotic applications.